2001 TOYOTA PRIUS air conditioning

DI±898
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2001 PRIUS (RM778U)
3 Check harness and connector between A/C amplifier and compressor lock sen-
sor (See page IN±41).
NG Repair or replace harness or connector.
OK
Proceed to next circuit inspection shown on problem symptoms table (See page DI±874). Howev-
er, if DTC 22 is displayed, check and replace A/C amplifier.

I08340
J1
J/CL±Y
A3
A/C Dual Pressure
SwitchA/C amplifier
W±B
IE1
A811
PSW
4
ED 115
A W±B
± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±899
2001 PRIUS (RM778U)
DTC 23 Pressure Switch Circuit
CIRCUIT DESCRIPTION
This pressure switch sends the appropriate signals to the A/C amplifier when the A/C refrigerant pressure
drops too low or rises too high. When the A/C amplifier receives these signals, if outputs signals via the A/C
amplifier to switch off the compressor relay and turns the magnetic clutch off.
DTC No.Detection ItemTrouble Area

Open inpressure sensor circuit
Pressure switch
23

Open in pressure sensor circuit.

Abnormal refri
gerant pressure.
Pressure switch

Harness or connector between pressure switch and A/C am-
lifi23
Abnormal refrigerant ressure.
below 196 kPa (2.0 kgf/cm2. 28 psi)2
plifier


Refrigerantpipe lineover 3,140 kPa (32.0 kgf/cm2. 455 psi)
Refrigerant pipe line

A/C amplifier
WIRING DIAGRAM

DI7SB±01

I18170
ON
PSW
(±) (+)
Low Pressure Cut SideReferaence : High Pressure Cut SIde
ON (0 V)
OFF (12V) 196 kPa225 kPaON (0 V)
2,550 kPa
OFF (12V)3,140 kPa
DI±900
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check voltage between terminals PSW of A/C amplifier and body ground.
PREPARATION:
(a) Install the manifold gauge set (See page AC±18).
(b) Remove the center cluster module control with connec-
tors still connected.
(c) Turn ignition switch ON.
CHECK:
Check voltage between terminals PSW of A/C amplifier con-
nector and body ground when refrigerant pressure is changed.
OK:
The voltage changes refrigerant pressure, as shown
in the chart below.
OK Proceed to next circuit inspection shown on
problem symptoms table (See page DI±874).
NG

I18025
1
2
3
4
Low Pressure Cut Side
196 kPa225 kPa2,550 kPa
3,140 kPaOFF (No continuity) OFF (No continuity)ON (Continuity)
ON (Continuity)
Referaence : High Pressure Cut SIde
± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±901
2001 PRIUS (RM778U)
2 Check pressure switch.
PREPARATION:
Disconnect pressure switch connector.
CHECK:
Check continuity between terminals 1 and 4 of pressure switch
when refrigerant is changed.
OK:
The continuity changes with refrigerant pressure as
shown in the chart below.
NG Replace pressure switch.
OK
3 Check harness and connector between A/C amplifier and pressure switch, pres-
sure switch and body ground (See page IN±41).
NG Repair or replace harness or connector.
OK
Check and replace A/C amplifier.

4(V)
1
0
100%
TPI terminal voltage
Damper opening angle
I18402
A16
Air Mix Control
Servomotor
A/C Amplifier
6
S5TP
SGTP
TP 17
15
A916 A9A9
II1
3
B
V 21W
W±R
BR±WW 8
II1
W 7
II1 Y±R DI±902
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2001 PRIUS (RM778U)
DTC 31, 41 Air Mix Damper Position Sensor Circuit
CIRCUIT DESCRIPTION
This sensor detects the position of the air mix damper and
sends the appropriate signals to the A/C amplifier. The position
sensor is built into the air mix control servomotor.
DTC No.Detection ItemTrouble Area
31Short to ground or power source circuit in air mix damper posi-
tion sensor circuit.
Air mix damper position sensor.

Harness of connector between air mix control servomotor and
41Air mix damper position sensor value does not change even if
Harness of connector between air mix control servomotor and
A/C amplifier.41Air mix dam er osition sensor value does not change even if
A/C amplifier operates air mix control servomotor.
A/C amplifier.
WIRING DIAGRAM
DI7SC±01

I18165
SGTP
TPON
(+)(±)
± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±903
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check voltage between terminals TP and SGTP of A/C amplifier connector.
PREPARATION:
(a) Remove center cluster module control with connectors
still connected.
(b) Turn ignition switch ON.
CHECK:
Change the set temperature to activate the air mix damper, and
measure the voltage between terminals TP and SGTP of A/C
amplifier connector each time when the set temperature is
changed.
OK:
Set TemperatureVoltage
Max. COOL3.5 ± 4.5 V
Max. WARM0.5 ± 1.8 V
HINT:
As the set temperature increases, the voltage decreases grad-
ually without interruption.
NG Go to step 2.
OK
Proceed to next circuit inspection shown on problem symptoms table (See page DI±874).
However, if DTC 31 or 41 is displayed, check and replace A/C amplifier.

I1907632 1COOL
WARM
DI±904
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2001 PRIUS (RM778U)
2 Check air mix damper position sensor.
PREPARATION:
Remove air mix control servomotor (See page AC±56).
CHECK:
Measure resistance between terminals 1 and 2 of air mix control
servomotor connector.
OK:
Resistance : 4.2 ± 7.8 kW
CHECK:
While operating air mix control servomotor as shown in the pro-
cedure on page DI±906, measure resistance between termi-
nals 2 and 3 of air mix control servomotor connector.
OK:
PositionResistance
Max. COOL3.6 ± 6.7 kW
Max. WARM0.6 ± 1.1 kW
HINT:
As the air mix control servomotor moves from cool side to hot
side, the resistance decreases gradually without interruption.
NG Replace air mix control servomotor.
OK
3 Check harness and connector between A/C amplifier and air mix control servo-
motor (See page IN±41).
NG Repair or replace harness or connector.
OK
Check and replace A/C amplifier.

4
1
0
100%Damper opening angle4.1 V
0.9 V
TPI terminal voltage (V)
I14169
A/C Control Assembly A14
Air Inlet Control
Servomotor
A9
S5TPI 19
SGTPI A9
2 118
18TPI
A9 W
3
W
W
± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±905
2001 PRIUS (RM778U)
DTC 32, 42 Air Inlet Damper Position Sensor Circuit
CIRCUIT DESCRIPTION
This sensor detects the position of the air inlet damper and
sends the appropriate signals to the A/C amplifier. The position
sensor is built into the air inlet control servomotor.
DTC No.Detection ItemTrouble Area
32Short to ground or power source circuit in air inlet damper posi-
Air inlet damperposition sensor32Short to ground or ower source circuit in air inlet dam er osi
tion sensor circuit.

Air inlet damper position sensor

Harness or connector between air inlet control servomotor
42Air inlet damper position sensor value does not change even if
A/C amplifier operates air inlet control servomotor.
Harness or connector between air inlet control servomotor
and A/C amplifier

A/C amplifier
WIRING DIAGRAM
DI7SD±01